Home - News - Industry News - Analysis of the Principle, Types, and Engineering Applications of Blind Flanges
June 05, 2025
A blind flange is a flange disc without a central through-hole, essentially a circular metal plate with bolt holes on its edge. It forms a closed end by connecting with matching flanges via bolts. Its core function is to block the flow of media in pipelines or equipment and achieve pressure sealing through the combination of the sealing surface and gaskets.
· Sealing Mechanism: The pre-tightening force of bolts causes the gasket to elastically deform, filling the micro-gaps on the flange sealing surface to prevent media leakage. Different working conditions require matching appropriate sealing surface types and gasket materials.
· Permanent Blockage: Used to permanently seal pipeline ends or abandoned interfaces, such as the final sealing of a pipeline system after completion.
· Temporary Isolation: Temporarily blocks a pipeline section during maintenance, testing, or segmented operation to facilitate servicing—for example, isolating non-test areas during pipeline pressure testing.
· Safety Isolation: Provides reliable isolation in pipelines carrying hazardous media to prevent leaks and related accidents.
· Pressure and Temperature Matching: Select blind flanges of corresponding pressure and temperature ratings based on pipeline design parameters to avoid seal failure due to overpressure or high temperatures.
· Bolt Preload Control: Tighten bolts evenly to prevent flange deformation or gasket damage from uneven stress. Use a torque wrench to follow standard torque specifications.
· Labeling and Management: Mark blind flanges with "Blind Flange" and installation dates, and maintain a log to record their locations and purposes to prevent misoperation.
· Anti-Corrosion Treatment: Apply anti-corrosion coatings to metal blind flanges in outdoor or corrosive environments to extend their service life.
· End Sealing: Blind flanges close pipeline ends after installation to prevent debris ingress or media leakage.
· Sectional Isolation: Installed at connection points in large pipeline systems to isolate maintenance sections and avoid full-system shutdowns.
· Pressure Testing: Seals both ends of the test section during pipeline hydrostatic testing to ensure stable pressure and leak-proof conditions.
· Reactor Isolation: Installed on spare interfaces of chemical reactors to prevent hazardous media leaks and facilitate future modifications.
· Storage Tank Isolation: Separates storage tanks from pipelines during maintenance to ensure safety.
· Emergency Blockage: Rapidly installed to stop media flow in case of pipeline leaks, preventing accident escalation.
· Boiler Pipeline Maintenance: High-temperature alloy blind flanges are used for temporary drain pipes or spare interfaces in power plant boilers to meet isolation needs during startup and shutdown.
· Steam Pipeline Segmentation: Installed in long-distance steam pipelines to enable sectional thermal insulation maintenance and reduce heat loss.
· Sewage Pipeline Blockage: Plastic blind flanges offer corrosion resistance and low cost for temporary sealing in sewage systems.
· Seawater Desalination: Stainless steel blind flanges resist seawater corrosion, suitable for pipeline isolation in coastal desalination equipment.
As a critical component in industrial pipeline systems, blind flanges ensure media blockage and safety isolation through structural closure and sealing reliability. Type selection must integrate pressure, temperature, media properties, and maintenance requirements, while strict adherence to design codes and safety standards in engineering applications guarantees system stability. With advancements in materials and manufacturing, high-performance blind flanges will play an increasingly vital role in complex industrial scenarios.
